ABSTRACT
The controlled vapor hydrolysis of LiAlH4 has been investigated as a safe and predictable method to generate hydrogen for mobile fuel cell applications. A purpose-built vapor hydrolysis cell manufactured by Intelligent Energy Ltd. was used as the reaction vessel. Vapor was created by using saturated salt solutions to generate humidity in the range of 46-96% RH. The hydrolysis products were analyzed by thermogravimetric analysis (TGA) and powder X-ray diffraction and compared with possible hydroxide-based phases characterized using the same methods. Analysis of the products of the LiAlH4 vapor hydrolysis reaction at a relative humidity in excess of 56% indicated complete decomposition of the LiAlH4 phase and formation of the hydrated layered double hydroxide, [LiAl2(OH)6]2CO3·3H2O, rather than the simple salts, LiOH and Al(OH)3, previously suggested by the literature. The high level of hydration of the layered double hydroxide (LDH) (12% wt water) and the presence of carbonate indicated that the feed stream was contaminated with CO2 and that the highly hydrated and hygroscopic product would be detrimental to the mobile hydrogen production process, restricting recyclability of the water fuel cell byproduct and lowering the gravimetric density of LiAlH4. Carrying out the vapor hydrolysis reaction in a glovebox in the absence of CO2 indicated that the hydroxide derivative of the LDH, [LiAl2(OH)6]OH·2H2O, could be formed instead, but the water content was even more significant, equating to 17% of the carried weight. TGA showed that water was retained up to 300 and 320 °C in the two phases, making thermal recycling of the water retained impractical and casting doubt on whether generating hydrogen on the move by vapor hydrolysis of LiAlH4 is practical.
ABSTRACT
Little is known about the way in which mandated and heavy-drinking voluntary students comparatively respond to peer-led brief motivational interventions (BMIs) and the mediators and moderators of intervention effects. Research suggests that mandated students may be more defensive due to their involvement in treatment against their will and this defensiveness, in turn, may relate to treatment outcome. Furthermore, it is not clear how mandated and heavy-drinking voluntary students perceived satisfaction with peer-led BMIs relates to treatment outcomes. Using data from two separate randomized controlled trials, heavy drinking college students (heavy-drinking voluntary, n = 156; mandated, n = 82) completed a peer-led brief motivational intervention (BMI). Both mandated and heavy-drinking volunteer students significantly reduced drinking behaviors at 3-month follow-up, reported high levels of post-intervention session satisfaction, yet no effects for mediation or moderation were found. Findings offer continued support for using peer counselors to deliver BMIs; however, results regarding the mechanisms of change were in contrast to previous findings. Implications for treatment and future areas of research are discussed.
